Dell did a 2 dp port 5k monitor at that time and it was buggy and had various issues. Apple did not use two controllers, but instead a custom one for a real 5k image on a single screen. There was no port or a cable that supported that at the time 5K iMac came out.
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I cannot believe there's no way to use a 27" 2015 iMac as a second display
- Thread starter ronrather
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Dell did a 2 dp port 5k monitor at that time and it was buggy and had various issues. Apple did not use two controllers, but instead a custom one for a real 5k image on a single screen. There was no port or a cable that supported that at the time 5K iMac came out.
Of course they are not, but that also doesn’t mean they deliberately make their products worse than they were just so that, hypothetically, one day when they start making 5K monitors (which they wouldn’t start doing for several years) they could “force you to buy it instead”.
It’s much more plausible they just couldn’t do it in a way they wanted to at the time.
Show us on the doll where Apple hurt you. Was it the butt?
Yes as they ripped my wallet out of my back pocket
Great response to someone who sounds like he created a new account just to do some trolling.
I suppose one could read that somewhere and assume it's true. Or one could actually examine such a machine to obtain the correct info.
Did Apple make a custom GPU to connect to this custom controller? No. It's a regular GPU with multiple DisplayPort (and possibly HDMI) outputs. Those outputs may connect to the custom controller that you refer to but the result is the same - any GPU should be able to make the same connection(s).
I have AGDCDiagnose output for many tiled displays including a few iMac 5K displays (product IDs ae12 and ae1e).
They have two ports / DisplayPort connections from the GPU:
Code:
* 1: [DP 1.2 4 x HBR2] Status: [4 x HBR2 7777] caps [features 0x101001b, p_encoding 0xd] Sink OUI:000-016-250 MN27h1 [077-078-050-055-104-049] HW Version: 16 FW Version: 1.2
* 2: [DP 1.2 4 x HBR2] Status: [4 x HBR2 7777] caps [features 0x101001b, p_encoding 0xd] Sink OUI:000-016-250 MN27h1 [077-078-050-055-104-049] HW Version: 16 FW Version: 1.2Each port has separate DPCD and EDID info.
The DPCD info has the connection info (each is 4 lanes of HBR2). The OUI for each DisplayPort sink device is 000-016-250 which is "Apple, Inc." That's their custom controller(s) I guess.
The EDIDs contain timings and tile information. One has the left 2560x2880 tile and single-tile resolutions. The other has the right 2560x2880 tile.
There's a 2048x2304 timing in each EDID which could be a tile for a 4096x2304 image? Or maybe a 2Kx2K picture by picture mode?
The iMac 5K displays don't appear to have corresponding .mtdd files in the displays overrides directory like other tiled displays. An .mtdd file usually contains an overlay EDID. The overlay EDID could be stored elsewhere or calculated from the tiled EDIDs. The overlay EDID contains a faked 5K timing to represent the tiled display mode. The Apple Pro Display XDR has a really complicated .mtdd file because of all the modes (tiled and non-tiled) it supports.
If you have an iMac 5K display that is not ae12 or ae1e then please use AllRez to grab all the info for the displays (it includes the AGDCDiagnose output), zip the result, and post here for examination.
Lol, I don’t have an iMac 5K.
So, what is your theory - they deliberately made this impossible because 5, 6 years later they might sell a monitor that they think would be sold less if people with 5K iMacs would use those instead?
He wasn't talking about you. But the person you responded to who registered 3 months ago. Check again
He quote responded me 🤷🏻♂️He wasn't talking about you. But the person you responded to who registered 3 months ago. Check again
Yes, I was complimenting you on giving a good comeback to someone who was trolling you, so I quoted your comeback. So much for trying to support you on this 😐.
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Interesting. I tried it and it works. But as far as I can see, it's just screen mirroring, rather than a separate screen.
The video description says 2015 and later iMacs cannot use this method.
If you really wish to use the late 2015 27" iMac. You should not waste time searching for a way that does not exist.
When there is a good solution.
Remove the parts inside and build you own 5k Display.
That is what I and many others have already done. I am still using my DIY 5k Display. I got the speakers working as well. All that is missing, compared to say Studio Display, is the camera and microphone.
If this is not an option that is acceptable, then pass it on, or sell it. 🤷♂️
When there is a good solution.
Remove the parts inside and build you own 5k Display.
That is what I and many others have already done. I am still using my DIY 5k Display. I got the speakers working as well. All that is missing, compared to say Studio Display, is the camera and microphone.
If this is not an option that is acceptable, then pass it on, or sell it. 🤷♂️
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As a practical matter, for those who have a late-model higher-spec'd iMac, it might make more sense to sell it and buy a used ASD. That's what I may do.
I've seen used ASD's on Craig's List for $800, some still with AC+, and I could probably get close to that for my 2019 i9 iMac with its 2 TB SSD and 128 GB RAM. Even if I could only get $600, that's just $200 to swap a used 2019 iMac for a used ~2023 ASD.
I've seen used ASD's on Craig's List for $800, some still with AC+, and I could probably get close to that for my 2019 i9 iMac with its 2 TB SSD and 128 GB RAM. Even if I could only get $600, that's just $200 to swap a used 2019 iMac for a used ~2023 ASD.
That might be a reason. Other possible reasons:
- In 2014, they didn't have a single port that could handle 5K60.
- They didn't want to add ports to the iMac that were only used for Target Display Mode.
- Connecting two Thunderbolt cables from one Mac to the other is weird or doesn't work.
- A bunch of extra circuitry would be required. Two or four 10 Gbps DisplayPort MUX controlled by a switch, GPIO, I2C, or DDC (through DisplayPort Aux Channel).
You can probably connect two DisplayPort cables to the Thunderbolt 2 ports. The iMac can determine if the device is a SINK or a SOURCE. If it's a SOURCE, then the iMac can switch all the DisplayPort MUXs to create a path to its dual DisplayPort SINK. Audio over DisplayPort may be difficult. I wonder how the original iMacs handled that? They have a DisplayPort sink that supports audio? Or does the iMac have software to capture the audio from DisplayPort?
Circuitry to do Thunderbolt Target Display Mode instead of DisplayPort Target Display Mode would be more complicated. The original Thunderbolt iMacs had Thunderbolt 1 controllers with two DisplayPort In Adapters and a DisplayPort Out Adapter for Thunderbolt Target Display Mode. Thunderbolt host controllers usually don't have a DisplayPort Out Adapter or they only have one so multiple Thunderbolt peripheral controllers would need to be added. The software to do the Thunderbolt path setup would be more complicated. I don't know if it's possible to setup a cross-domain path that reaches deeper into the other Thunderbolt domain.
Incorrect.
I have been using screen sharing in various resolutions - including 4k when needed - ever since it was introduced.
In fact, I'm doing it right now.
Yes, HiDPI also works if the Mac being screen shared is AS. But higher resolutions are still there even if using Intel to Intel. No, it's not HDR, but neither is the target iMac talked about in this thread.
I do think Apple probably hides some functionality if the Mac is headless, with the upshot that sometimes tinkering with settings and configurations is needed to unlock what you want/need. What I might have done to get into this working state, I cannot recall. But again, I am doing this right now. It works, and it works decently.
One thing to check is FPS; one display mode I was in did not display other options until I turned down the FPS from 60 to 30.
Did miss the part about this OP wanting a second screen; I have recollections of being able to do so in the past but haven't tried recently as it's not something I need.
But overall, one need not just throw a retina iMac into the trash. It still has mileage in it, even if it's relegated to being a smart terminal for another AS Mac.
OK, I remember what I did years ago to make screen sharing work at all sorts of resolutions now.
Mac minis need to sense a monitor attached to them in order to get the GPU to do its thing. Now, you don't actually need to attach a monitor, but a $5-8 "EDID emulator" which goes into your HDMI port does the trick.
They're easily found on Amazon.
This has worked so well, I'd completely forgotten that I did it.
As far as the OPs desire for a second screen, looks like that can work in High Performance screen sharing, but that's between two AS Macs only. There may be other ways of making it work on Intel/Intel & AS/Intel, but I haven't looked to be honest.
Again, no need to throw away that nice Retina iMac - it has uses.
Mac minis need to sense a monitor attached to them in order to get the GPU to do its thing. Now, you don't actually need to attach a monitor, but a $5-8 "EDID emulator" which goes into your HDMI port does the trick.
They're easily found on Amazon.
This has worked so well, I'd completely forgotten that I did it.
As far as the OPs desire for a second screen, looks like that can work in High Performance screen sharing, but that's between two AS Macs only. There may be other ways of making it work on Intel/Intel & AS/Intel, but I haven't looked to be honest.
Again, no need to throw away that nice Retina iMac - it has uses.
For those afflicted by tldr, the short answer is 'apparently not'
Here's the longer answer.
Point 1: Apple's minimum system requirement for Airplay (to iMac) is iMac introduced in 2019 or later.
Point 2: One of the earliest posts suggested:
as a method to allow iMac use as external monitor.
I combined points 1 & 2 and interpreted them as meaning: updating to a recent macOS (Sonoma in my case) would allow/trick iMacs older than Apple's minimum system requirements to become Airplay receivers.
For my late-2015 iMac, this does not seem to be the case. Apple's instructions for setting up Airplay are:
- macOS Ventura or later: choose Apple menu > System Settings, click General in the sidebar, then click AirDrop & Handoff on the right. Turn on AirPlay Receiver.
You can use OCLP to turn on Airplay to Mac on the 2015 with Monterey to get OCLP working. I think that I tested this out on my 2015 MacBook Pro. The other free alternative is to create a virtual desktop on the other system using Better Display and then screen sharing into it from the iMac.
I've used Airplay to Mac from my M1 Studio to my iMac Pro and it works really well over Ethernet. I could also connect a Thunderbolt 4 cable between them to decrease the bandwidth on my LAN. I suppose I should try this with my 2015 iMac 27. It's sitting on my testing desk right now and I haven't used it since getting the iMac Pro.
I've used Airplay to Mac from my M1 Studio to my iMac Pro and it works really well over Ethernet. I could also connect a Thunderbolt 4 cable between them to decrease the bandwidth on my LAN. I suppose I should try this with my 2015 iMac 27. It's sitting on my testing desk right now and I haven't used it since getting the iMac Pro.
Then don't buy. Why do you WHINE about it? Do you think whining here will change Apple's mind?
I know! Lets start a PETITION! That always works.
And since I am not oh so alt and edgy, I lost the credentials to my former account. But in your martyrdom, I must have signed up just to troll you. How in the world do you get that fat head thru doors?